[censored], of all the things to happen when first firing an engine and breaking in the cam that's one of the worst! No one needs that kind of stress especially at our age. I would have to see them side by side, but I think your right that your new mount looks thicker than a factory mount. One thing I would ad is to make sure the timing is close and especially that it's not running lean at the part throttle setting that is required for cam break-in. I have seen manifolds glow red when not set up right.